The present invention relates to a confocal endoscope system capable of obtaining an observation image through a confocal optical system.
Devices for medical diagnostic purposes configured to superimpose scale information for measuring an object on an observation image have been proposed. Such a device is provided with a probe to be inserted into a body cavity of a subject to obtain the observation image. For example, Japanese Patent Publication No. 3396165 (hereafter, referred to as JP3396165) discloses an ultrasonic diagnostic device capable of superimposing a scale on an image generated based on ultrasonic waves reflected from a body cavity.
Recently, a confocal endoscope system having a confocal optical system capable of generating an observation image having a resolution and a scaling factor higher than those of an observation image generated through a normal observation optical system has been proposed. More specifically, the confocal endoscope system is configured to illuminate tissue in a body cavity, to receive only part of light passing through a pinhole located at a position conjugate with a focal point of the confocal optical system, and to generate an image based on a signal having the amplitude corresponding to the intensity of the light received through the pinhole.
In addition, the confocal endoscope system is capable of shifting the focal point by a minute amount in a direction of an optical axis (i.e., in a direction of a depth of a region being observed) so that observation of tissue at a depth of up to 250 μm from a surface of the tissue can be achieved. There is a demand for three-dimensional representation of an image of the tissue within the illuminated area by combining a plurality of images obtained by shifting the focal point in the direction of the depth of the tissue.
To put the confocal endoscope system to practical use, it is preferable that the confocal endoscope system has a function of precisely measuring the size of tissue including a region predicted to be affected and a function of generating a cross sectional image of the tissue along a direction of a depth of the tissue so as to enable an operator to quickly and precisely locate the affected region from the observation image.
The configuration disclosed in JP3396165 can only be applied to the ultrasonic diagnostic device having a specific configuration, and therefore can not be applied to the confocal endoscope system capable of generating an observation image having a high resolution and a high scaling factor.